THE MASS OF Kepler-93b AND THE COMPOSITION OF TERRESTRIAL PLANETS

By C. Dressing, D. Charbonneau, Xavier Dumusque, S. Gettel, F. Pepe, A. Collier Cameron, D. Latham, E. Molinari, S. Udry, L. Affer and 25 more. 2014

167 citations recorded by the source corpus.

Kepler-93b is a 1.478 ± 0.019 R⊕ planet with a 4.7 day period around a bright (V = 10.2), astroseismically characterized host star with a mass of 0.911 ± 0.033 M☉ and a radius of 0.919 ± 0.011 R☉. Based on 86 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 32 archival Keck/HIRES observations, we present a precise mass estimate of 4.02 ± 0.68 M⊕. The corresponding high density of 6.88 ± 1.18 g cm−3 is consistent with a rocky composition of primarily iron and magnesium silicate. We compare Kepler-93b to other dense planets with well-constrained parameters and find that between 1 and 6 M⊕, all dense planets including the Earth and Venus are well-described by the same fixed ratio of iron to magnesium silicate. There are as of yet no examples of such planets with masses >6 M⊕. All known planets in this mass regime have lower densities requiring significant fractions of volatiles or H/He gas. We also constrain the mass and period of the outer companion in the Kepler-93 system from the long-term radial velocity trend and archival adaptive optics images. As the sample of dense planets with well-constrained masses and radii continues to grow, we will be able to test whether the fixed compositional model found for the seven dense planets considered in this paper extends to the full population of 1–6 M⊕ planets.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/207d26f16426f1d27f65b542246887182b6bbb34

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. J. Owen
2. J. Johnson
3. Timothy Morton
4. Yanqin Wu
5. Andrew W. Howard
6. C. Mordasini
7. B. Fulton
8. E. Petigura

In Instrumentation

1. J. Owen
2. J. Johnson
3. B. Fulton
4. Timothy Morton
5. E. Petigura
6. Andrew W. Howard
7. C. Mordasini
8. Sheng Jin

In Statistical and Nonlinear Physics

1. S. Lépine
2. J. Owen
3. C. Mordasini
4. Y. Lithwick
5. J. Johnson
6. Keivan G. Stassun
7. Sheng Jin
8. Yanqin Wu

Citations in the corpus

• Multiple Disk Gaps and Rings Generated by a Single Super-Earth (2017, background): “These planets generally weigh less than 20M⊕, as determined from transit-timing analyses (e.g., Jontof-Hutter et al. 2014; Wu & Lithwick 2013) and radial velocity measurements (e.g., Weiss & Marcy 2014; Marcy et al. 2014; Dumusque et al. 2014; Dressing et al. 2015).”
• Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes (2016, background): “Indeed, the most precise estimates of the masses and radii of the smallest planets reveal densities that are consistent with a Mg-Si-O composition that is identical to that of the Earth (Dressing et al. 2015).”
• Compositional Imprints in Density–Distance–Time: A Rocky Composition for Close-in Low-mass Exoplanets from the Location of the Valley of Evaporation (2017, background): “Among the extrasolar planets, the mass-radius relation for planets with radii less than 2.7 R⊕ and with masses known with an error less than 20 % are approximatively also compatible with such an Earth-like composition (Dressing et al. 2015; Motalebi et al. 2015; Buchhave et al. 2016).”
• Atmospheric characterization of Proxima b by coupling the Sphere high-contrast imager to the Espresso spectrograph (2016, background): “M⊕ objects on short-period orbits have an internal structure similar to Earth Article number, page 11 of 16 (e.g. Rogers 2015; Dressing et al. 2015).”
• Identifying Exoplanets with Deep Learning: A Five-planet Resonant Chain around Kepler-80 and an Eighth Planet around Kepler-90 (2017, background): “…et al. 2016; Thompson et al. 2017; Rowe et al. 2014; Morton et al. 2016), and significantly improved our understanding of the population of small planets in the inner parts of planetary systems (Marcy et al. 2014; Howard et al. 2012; Youdin 2011; Dressing et al. 2015; Wolfgang & Lopez 2015).”
• The Evaporation Valley in the Kepler Planets (2017, background): “This is consistent with RV results from known bare planets (e.g. Dressing et al. 2015).”
• PLANETARY CANDIDATES FROM THE FIRST YEAR OF THE K2 MISSION (2015, background): “…transiting planets are important for learning about the masses and compositions of small exoplanets through radial velocity measurements (Marcy et al. 2014; Dressing et al. 2015), and for learning about planetary atmospheres through transit spectroscopy (Knutson et al. 2014; Kreidberg et al. 2014).”
• Atmospheric Escape and the Evolution of Close-In Exoplanets (2018, background): “2 Owen, James E. comparison reveals that the planet is consistent with being entirely solid (e.g. Dressing et al. 2015); in other cases the planet has such a low density that it needs to have a significant (Earth radii or larger) atmosphere composed of Hydrogen/Helium gas (e.g. Wu & Lithwick 2013;…”
• Spacing of Kepler Planets: Sculpting by Dynamical Instability (2015, background): “This applies to planets with sizes of a few Earth radii, the vast majority of our sample, and recent studies show that this relation may even extend to planets as small as 1.4R⊕ (Dressing et al. 2014).”
• A NEARBY M STAR WITH THREE TRANSITING SUPER-EARTHS DISCOVERED BY K2 (2015, background): “The planets range in size from 2R⊕ to 1.5R⊕, indicating that they may span the gap between rock-dominated “Earths”/“super-Earths” and low-density “sub-Neptunes” with considerable volatile content (Marcy et al. 2014; Rogers 2014; Dressing et al. 2014).”
• Kepler Planet Masses and Eccentricities from TTV Analysis (2016, background): “…al. 2010; Hartman et al. 2011; Gautier et al. 2012; Gilliland et al. 2013; Pepe et al. 2013; Alonso et al. 2014; Barros et al. 2014; Dumusque et al. 2014; Kostov et al. 2014; Marcy et al. 2014; Moutou et al. 2014; Dressing et al. 2015; Esteves et al. 2015; Gettel et al. 2016; Sinukoff et al. 2016).”
• MASS–RADIUS RELATION FOR ROCKY PLANETS BASED ON PREM (2015, methodology): “…1.486± 0.035 (Carter et al. 2012) 0.37± 0.14 K-78b 1.86+0.38 −0.25 (Pepe et al. 2013) 1.173 +0.159 −0.089 (Pepe et al. 2013) 0.37 +0.3 −0.5 K-93b 4.02± 0.68 (Dressing et al. 2015) 1.478± 0.019 (Ballard et al. 2013) 0.26± 0.2 COROT-7b 5.74± 0.86 (Haywood et al. 2014) 1.585± 0.064 (Barros et…”